Thanks for the suggestions omni! I was hoping for some feedback so I could further optimize things. The measurements were taken indoors. Too cold for outdoor measuring here now. I used umik calibrated mic and my house is extremely quiet in the country. My version of REW is probably 3 months I'll update it and remeasure as you suggest as soon as I'm able. I'm afraid I am having some complications from a broken leg and I'll be stuck in the hospital here for awhile.
I look forward to see the new measurements 🙂 Are you measuring at 1 m distance? Is the amplifier quiet? Or is there considerable hiss without signal (that can give the observed behavior).
Get well soon!
/Anton
I did measure at 1 meter. Outdoors I would generally do 2 meters but inside the early reflections are a problem. The amp is very quiet, but only a 2 watt SET so I think I'll use a different amp for the next measurements. Perhaps the distortion profile of the SET is affecting the measurements? It will be a couple of weeks before I'll be able to get some measurements done. Thanks again for your suggestions. Craig
No, it has a different exit angle. But still might be worth a try. I did try selenium d220ti. Measured similarly except I believe not good so low in frequency if I'm remembering right, and lacked a lot of the easy refined character of the radian. Selenium exit angle does not match either.
About the distortion, yes it is most likely amplifier's distortion with H2 dominance, because it's so even and curve follows BSC.
I have been able to create also mic preamp overdrive distortion in nearfield measurements when spl gets close to 120db
I have been able to create also mic preamp overdrive distortion in nearfield measurements when spl gets close to 120db
That makes sense. Thanks for the tips. I can calibrate spl in rew easy enough, but how do I know that I'm giving it 2.83 volts during measurement? Will it measure across the speaker terminals consistently during a sweep? And for a 2 meter measurement I would need 11.32 volts? That's way too much to send to the compression driver with that crossover frequency I would think. Perhaps I should be keeping the output lower to avoid mic clipping as well and doing the math to get the 1 watt sensitivity. Any suggestions on just how to do that? What might be the best spl to measure? I know it's not apples to apples comparing distortion of these at 1 watt with distortion of a dome tweeter at 1 watt. It seems that to be comparable they should be at similar spls because mine will be idling along at much less than 1 watt almost all of the time during listening.
I have never checked voltage, no need for that with my active systems. Spl-calibrated mic and and specified distance is enough to evaluate final outcome, distortion % value is irrelevant . For comparison, measure some commercial speakers too. What interests me are the spikes in distortion, they tell mechanical resonances. Sometimes it is a loose window or bookself! Wider elevations tell usually about high excursion in the low end of passband. I test first individual drivers with and without eq and xo to find limits for passband.
Stardard and accurate signal voltage and spl are needed for speaker design and simulation. Measurement conditions should be standardized and performed in anechoid chamber or outdoors with low ambient noise.
Stardard and accurate signal voltage and spl are needed for speaker design and simulation. Measurement conditions should be standardized and performed in anechoid chamber or outdoors with low ambient noise.
Hi Craig - Sorry to hear of your hospital stay and medical problems , hope you are home And well! -- I understand how much fun hospitals and medical issues can be, I've got some medical problems as well.
I Really! like your Horn Speakers !!! - Great design choices , what materials did you use and how did you come up with the design for the bass cabinets?. It must be nice to have something that isn't just a square box - 🙂 - I first heard horn speakers in the early 1990's at a Stereophile Audio show in Los Angles I think , they were Bruce Edgar's horns, I loved how dynamic they were, so much different then regular speakers. I've been wanting to buy or build some Horns ever since then! Life has just conspired against me 🙄 Just didn't have the money, then the time, or the tools, then we moved and didn't have enough space in the living room, then it was money again - LOL ...... I am hoping to finally make some soon.... 😀
Best Regards,
Dean
I Really! like your Horn Speakers !!! - Great design choices , what materials did you use and how did you come up with the design for the bass cabinets?. It must be nice to have something that isn't just a square box - 🙂 - I first heard horn speakers in the early 1990's at a Stereophile Audio show in Los Angles I think , they were Bruce Edgar's horns, I loved how dynamic they were, so much different then regular speakers. I've been wanting to buy or build some Horns ever since then! Life has just conspired against me 🙄 Just didn't have the money, then the time, or the tools, then we moved and didn't have enough space in the living room, then it was money again - LOL ...... I am hoping to finally make some soon.... 😀
Best Regards,
Dean
Well here are some more-the back of the enclosure looks nice. But what IS it? A concrete former? I haven't been to South Dakota in so long, have to schedule a post-COVID trip to see distant relatives and hear these speakers.
Not sure if you are still around, I was away from the forum a bit so didn't notice. Lower cab is a cnc made skeleton with ribs that lock into a spine. Wish I had a photo handy. Then wrapped with 4 layers of 1/8 inch hardboard. The tension on the layers and the many ribs make the cabinet very solid. Please let me know if you are ever in the neighborhood! I am just now getting back into doing some more measurements to make sure xo is dialed in. I only have time to measure in winter, but then it's too darn cold to do outside.